It’s the name that turns many English-speakers off, but even people in Japan sometimes take issue the way Calpis can linger in your mouth.

Calpis, Japan’s most popular dairy-based soft drink, famously had to change its name overseas to “Calpico,” since the company figured that trying to market something that sounds like “cow piss” to English-speakers would be a tall task. In Japan, though, nobody snickers at the Calpis name, but some people do find it kind of gross for another reason.

It’s not the taste, a mild milk/yogurt flavor, that bothers anyone, though. No, the problem is that after drinking a glass of Calpis, some people say they can feel an unpleasant residue in their mouths. After a friend cited that as the reason he’s not a big Calpis fan, Japanese Twitter user @aiakzw looked into the matter, and found out the reason for the sensation.

@aiakzw learned that when a substance present in Calpis combines with human saliva, they can combine into a solidified compound. Specifically, as pointed out by Twitter user @camelotmerlin, it’s the combination of the lactoprotein casein, found in Calpis, with mucin, a glycoprotein in human saliva, that causes the phenomenon.

Luckily, the compound that forms isn’t dangerous in any way, so the worst thing it can do is make drinking Calpis unpleasant for some. However, not everyone notices any sort of residue when drinking Calpis, so it could be that depending on how much mucin your saliva contains, or how mist your mouth is, you may or may not experience the effect. However, if the sensation is pronounced enough to keep you from enjoying Calpis on its own, you could always try mixing it with alcohol, which has a pretty consistent track record making people not worry about little things.

Sources: Twitter/@aiakzw, Twitter/@camelotmerlin via Hachima Kiko
Photos ©SoraNews24